1. Field of the Invention
The present invention relates to an apparatus and method of cleaning a semiconductor wafer and, more particularly, to an apparatus and method of cleaning a semiconductor wafer that is effectively removes a developer containing a photoresist from the wafer after an exposed photoresist is developed during photolithography in semiconductor device fabrication processes.
2. Discussion of the Related Art
Photolithography is used to form the pattern of a semiconductor device. Specifically, a photoresist is coated on a wafer, and a photomask is aligned above the wafer. The photoresist is then exposed through the photomask and developed using a developer, followed by removal of the developer containing the photoresist. What remains is the pattern of a semiconductor device.
A cleaning solution is used to remove the developer after the development of the photoresist. This cleaning process is carried out in such a manner that the cleaning solution is supplied to the surface of the wafer containing the developer while the wafer is rotated at a high speed, to thereby clean the developer containing the photoresist residue.
Referring to FIG. 1, a conventional wafer cleaning apparatus is constructed in such a manner that, when an air valve 14 is opened by the operation of a switching solenoid 10, deionized water (D.I. water) used as a cleaning solution flows through a D.I. water supply line 16 from a D.I. water supply source 12, and is supplied through a D.I. water outlet 18 to the surface of the wafer 20 by free fall, while the wafer rotates at a high speed.
In the aforementioned conventional wafer cleaning apparatus, D.I. water which falls on the wafer removes the developer as the D.I. water moves along the surface of the wafer toward the wafer edge due to the centrifugal force generated by the high-speed rotation of the wafer.
In this cleaning method, however, the vertical force resulting from the free fall of the D.I. water works on only that region of the wafer where the D.I. water falls directly. As a result, additional time and larger quantities of D.I. water are required in order to clean the developer left in a groove of a pattern located at a region other than the region on which the D.I. water falls.